abap/heaplimit is a SAP Parameter attribute which is used to control if this limit is reached, wp will be killed at next chance information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This value specifies the memory amount in bytes. When this amount is
exceeded, a work process is restarted after completing a transaction
step. In a work process, heap memory (malloc) can be allocated for a
user context. If a user context releases this memory again, as the
operating system sees it, the memory still remains occupied by the
process, and is only available for other processes once the process
itself has ended.
Aim
Restart work processes as little as possible but avoid swap space
bottlenecks.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.